Comparisons are made between the NCEP Atmospheric Model Intercomparison Project (AMIP II) integration and the NCEP/DOE and NCEP/NCAR reanalyses products. Our reasoning is simple. One can quantify the degree to which observations impact a model integration by comparing a similar atmospheric model run using nearly the same boundary conditions forced with observational data. In essence, one can demonstrate how a model (in this case NCEP) creates its own troposphere and how this may or may not diverge from an observational estimate (e.g., reanalysis).

We will emphasize surface, pressure-level and deep-layer temperatures (e.g., observed and simulated Microwave Sounding Unit Temperatures). Our work will address measures of sensitivity, coupling and surface-troposphere coherence and trends from both the AMIP II and reanalysis data. We will compare these differences in temperature to independent data such as CARDS and the HADRT radiosonde datasets to help quantify episodes where the magnitude of observed temperature behavior (measured by independent observations) may have been attenuated in the reanalysis products.

This work was performed under the auspices of the U.S. Department of Energy by University of California Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.